The present invention is directed to the field of thermostats and more particularly to thermostats which modify a setpoint as a function of time.
Thermostats are well known devices for control of heating ventilating and air conditioning (HVAC) systems. Thermostats which modify the temperature setpoint as a function of time period, can be found, for example in U.S. Pat. No. 4,469,274 (Levine) issued Sep. 4, 1984 and assigned to Honeywell Inc.
A problem existed with such time-temperature thermostats in that they would repeat a cycle of setpoint temperatures over and over again. There was no way to presently temporarily modify the setpoint of a period occurring one or more periods later.